/*
 * Copyright 2007-2011 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.priox.sigar.server.item;

import org.springframework.batch.item.*;

/**
 * {@link ItemStreamReader} with a synchronized read method. Is useful when needing to synchronize on read in a concurrent environment.
 * 
 * @author Marten Deinum
 */
public class SynchronizedItemReader<T> implements ItemStreamReader<T> {

    private final ItemReader<T> delegate;

    /**
     * 
     * @param delegate delegate ItemReader which does the actual work.
     */
    public SynchronizedItemReader(final ItemReader<T> delegate) {
        super();
        this.delegate = delegate;
    }

    public synchronized T read() throws Exception, UnexpectedInputException, ParseException,
            NonTransientResourceException {
        return this.delegate.read();
    }

    public void open(final ExecutionContext executionContext) throws ItemStreamException {
        if (this.delegate instanceof ItemStream) {
            ((ItemStream) this.delegate).open(executionContext);
        }
    }

    public void update(final ExecutionContext executionContext) throws ItemStreamException {
        if (this.delegate instanceof ItemStream) {
            ((ItemStream) this.delegate).update(executionContext);
        }
    }

    public void close() throws ItemStreamException {
        if (this.delegate instanceof ItemStream) {
            ((ItemStream) this.delegate).close();
        }

    }
}
